- Email: [email protected]
Exploring the climate response to the Tambora in 1815 and the 1809 tropical eruption
Abstracts / Quaternary International 279-280 (2012) 233–345
ENVIRONMENTAL AND CLIMATIC CONTEXT IBERIAN NEANDERTHALS DURING THE MIS3
OF
NORTHEASTERN
Juan Manuel López-García. IPHES-URV, Spain E-mail address: [email protected]
In general, according to pollen analysis, the Marine Isotopic Stage 3 (MIS3) (ca. 60-30 ka) is characterized by a dynamic that alternates between phases of forest development and expansion of semi-arid areas in accordance with the warming and cooling, respectively, of the marine surface temperatures. In this context of rapid fluctuations are located the Neanderthals occupations in the northeastern of Iberian Peninsula. In this communication we are going to expose the environmental and climatic data obtained by means of the small vertebrates (herpetofauna and small mammals), the pollen and the large mammals analyses of two Neanderthals localities situated in the northeastern Iberia (the Abric Romani and the Teixoneres Cave). The Abric Romaní is a classical site with Neanderthal industries in a rock shelter, located some 45 km to the northwest of Barcelona. The shelter is carved in Quaternary travertine, and the Mousterian lithics preserved in the succession of layers provide evidence that Neanderthals occupied the site at different moments of MIS 3, about 60–40 ka. Teixoneres Cave is one of the cavities belonging to the karstic system called Toll caves. Located in the Moià village some 60 km to the north of Barcelona it forms a more than 2 km long galleries course that contain several archaeological deposits from different chronologies. The layers II and III related with the MIS3 have provided Mousterian industries and other evidence of Neanderthals occupations. The multiproxy study of these both sites could constitute a new approach of environmental and climatic context which the Neanderthals populations lived in Northeastern Iberia. ORBITAL- AND SUBORBITAL-SCALE CLIMATE VARIABILITY IN THE SOUTH-EASTERN NORTH AMERICA DURING THE LAST GLACIAL PERIOD: IMPACT ON THE VEGETATION Constancia López-Martínez. EPHE, UMR CNRS 5805 EPOC, Bordeaux 1 University, France E-mail address: [email protected]
Last glacial abrupt climate changes, defined as Dansgaard/Oeschger cycles and Heinrich Events have been documented in ice cores, marine sediments and continental deposits, generally from the Northern Hemisphere (1). While most North Atlantic paleoceanographic and paleoclimatic studies covering the last glacial period are centred in the northern and eastern part (1), less attention has been paid to the western midlatitudes (2). In particular last glacial eastern North American vegetation changes remain poorly known due to a lack of long continuous pollen records in this region (3). In this work we present the first high resolution reconstruction of the vegetation changes derived from the analysis of a pollen-rich marine core located in the subtropical western North Atlantic (MD99-2203, 34o58’N, 75o12’W) during Marine Isotope Stage 3. The pollen sequence indicates the dominance of a mixed conifer/deciduous forest, similar to the cool mixed forest defined by (4), over the whole studied interval. Changes in the relative abundance of boreal and temperate-deciduous components exhibit a markedly influence of the precession on forest composition, with maximum abundance of deciduous types during Greenland Interstadial 78. Comparison with published high resolution marine pollen records from the subtropical eastern North Atlantic region (5) suggests smoother millennial-scale changes in forest cover in south-eastern North America. The frequency and amplitude of these vegetation changes in North Carolina suggest that the climatic variability of this region differs from that observed in Florida.
289
essential for proper conservation and management, but environmental policies still do not consider long-term ecological studies. Here we present the application of multi-proxy analyses to a 115 cm-thick core from La Molina mire (Alto de la Espina) located in NW Iberia, with a chronology spanning from the local Iron Age (ca. 2500 cal BP) to the present. The mire is located in an area intensively mined for gold during the Roman period, and close to a water-canalization system used for mining operations at that time. Our aim was to get insights into the development of the wetland by combining hydro-hygrophytes, nonpollen palynomorphs and geochemical analyses, supported by 14C datings and multivariate statistics (PCA). The results indicated a complex pattern of ecological succession. First, the data suggest the wetland was a minerogenic mire in the Iron Age. After that, and since Roman times, it was subjected to dramatic hydrological changes due to the rise of the watertable, fluctuating between the presence of open water and several phases of drawdown. Finally, by ca. 1350 years ago, the wetland experienced a rapid evolution towards ombrotrophy. High grazing pressure was also detected for the last 100 years. The significant change occurred during Early Roman Empire seems to have been the consequence of the direct use of the wetland as a water-reservoir of the canalisation system used for gold-mining. Thus, the current nature of the mire may be the result of an anthropogenic forcing; although multiple anthropogenic and natural causes were potentially linked to the shifts detected, which at least in three phases supposed a threshold response. Our investigation suggests that palaeoecological research is necessary to understand the origin of wetlands ecosystems, their long-term ecology and the role played by human activities. EXPLORING THE CLIMATE RESPONSE TO THE TAMBORA IN 1815 AND THE 1809 TROPICAL ERUPTION Stephan Lorenz. MPI for Meteorology, United Kingdom E-mail address: [email protected]
The largest historic volcanic eruption with known origin was the explosion of Mount Tambora in Indonesia in April 1815. In the aftermath of this devastating eruption, the following year 1816 came to be known as the "year without a summer", in particular in USA, Canada, and Europe, where the worst famine over a century as well as typhus epidemics accompanied by enhanced emigration from Europe were recorded. The stratospheric aerosol mass load was estimated to be about three times that of the Pinatubo eruption in 1991, leading to a strong impact on the Earth's climate system. The additional contribution of the large volcanic eruption with tropical but unknown location occurred in 1809, i.e., six years prior to the Tambora, is not well understood. In a series of ensemble simulations we applied the Earth system model developed at the Max-Planck-Institute for Meteorology, based on the ECHAM5/MPIOM model family, to investigate the combined contribution of the Tambora and 1809 eruptions to the relatively cool climate during the 19th century. However, ensemble simulations of complex circulation models are associated with a large ensemble spread in air temperature on a hemispheric and global as well as on a regional scale, with limited to very strong atmospheric response to volcanic aerosols. The unique path of the climate evolution through the Earth's history yielding the extreme summer in 1816 in North America and Europe is compared with the simulations. A special focus of our analysis is the volcanic impact on climate and its relationship with the status of the climate system, e.g. the ocean circulation, at the time of the eruption. LATE QUATERNARY MEGAFAUNA EXTINCTIONS, AND SURVIVALS
POPULATION
DYNAMICS,
ANTHROPOGENIC FORCING IN WETLANDS: A CASE STUDY IN NW IBERIA
Eline Lorenzen. Centre for GeoGenetics, University of Copenhagen, Denmark
Lourdes Lopez-Merino. Institute for the Environment, Brunel University, United Kingdom
The discussion of the causes underling the Late Quaternary megafauna extinctions has focused primarily on the roles of climate versus humans. Alternative drivers include an extraterrestrial impact, interspecific competition, or hyperdisease. Here we present the first large-scale comparative study addressing the LQ extinctions in the northern hemisphere, using data from several megafauna species.
E-mail address: [email protected]
Wetlands are exceptional ecosystems that contribute to biodiversity and play a key role in the hydrological cycle. Knowledge of their ecology is
E-mail address: [email protected]
ENVIRONMENTAL AND CLIMATIC CONTEXT IBERIAN NEANDERTHALS DURING THE MIS3
OF
NORTHEASTERN
Juan Manuel López-García. IPHES-URV, Spain E-mail address: [email protected]
In general, according to pollen analysis, the Marine Isotopic Stage 3 (MIS3) (ca. 60-30 ka) is characterized by a dynamic that alternates between phases of forest development and expansion of semi-arid areas in accordance with the warming and cooling, respectively, of the marine surface temperatures. In this context of rapid fluctuations are located the Neanderthals occupations in the northeastern of Iberian Peninsula. In this communication we are going to expose the environmental and climatic data obtained by means of the small vertebrates (herpetofauna and small mammals), the pollen and the large mammals analyses of two Neanderthals localities situated in the northeastern Iberia (the Abric Romani and the Teixoneres Cave). The Abric Romaní is a classical site with Neanderthal industries in a rock shelter, located some 45 km to the northwest of Barcelona. The shelter is carved in Quaternary travertine, and the Mousterian lithics preserved in the succession of layers provide evidence that Neanderthals occupied the site at different moments of MIS 3, about 60–40 ka. Teixoneres Cave is one of the cavities belonging to the karstic system called Toll caves. Located in the Moià village some 60 km to the north of Barcelona it forms a more than 2 km long galleries course that contain several archaeological deposits from different chronologies. The layers II and III related with the MIS3 have provided Mousterian industries and other evidence of Neanderthals occupations. The multiproxy study of these both sites could constitute a new approach of environmental and climatic context which the Neanderthals populations lived in Northeastern Iberia. ORBITAL- AND SUBORBITAL-SCALE CLIMATE VARIABILITY IN THE SOUTH-EASTERN NORTH AMERICA DURING THE LAST GLACIAL PERIOD: IMPACT ON THE VEGETATION Constancia López-Martínez. EPHE, UMR CNRS 5805 EPOC, Bordeaux 1 University, France E-mail address: [email protected]
Last glacial abrupt climate changes, defined as Dansgaard/Oeschger cycles and Heinrich Events have been documented in ice cores, marine sediments and continental deposits, generally from the Northern Hemisphere (1). While most North Atlantic paleoceanographic and paleoclimatic studies covering the last glacial period are centred in the northern and eastern part (1), less attention has been paid to the western midlatitudes (2). In particular last glacial eastern North American vegetation changes remain poorly known due to a lack of long continuous pollen records in this region (3). In this work we present the first high resolution reconstruction of the vegetation changes derived from the analysis of a pollen-rich marine core located in the subtropical western North Atlantic (MD99-2203, 34o58’N, 75o12’W) during Marine Isotope Stage 3. The pollen sequence indicates the dominance of a mixed conifer/deciduous forest, similar to the cool mixed forest defined by (4), over the whole studied interval. Changes in the relative abundance of boreal and temperate-deciduous components exhibit a markedly influence of the precession on forest composition, with maximum abundance of deciduous types during Greenland Interstadial 78. Comparison with published high resolution marine pollen records from the subtropical eastern North Atlantic region (5) suggests smoother millennial-scale changes in forest cover in south-eastern North America. The frequency and amplitude of these vegetation changes in North Carolina suggest that the climatic variability of this region differs from that observed in Florida.
289
essential for proper conservation and management, but environmental policies still do not consider long-term ecological studies. Here we present the application of multi-proxy analyses to a 115 cm-thick core from La Molina mire (Alto de la Espina) located in NW Iberia, with a chronology spanning from the local Iron Age (ca. 2500 cal BP) to the present. The mire is located in an area intensively mined for gold during the Roman period, and close to a water-canalization system used for mining operations at that time. Our aim was to get insights into the development of the wetland by combining hydro-hygrophytes, nonpollen palynomorphs and geochemical analyses, supported by 14C datings and multivariate statistics (PCA). The results indicated a complex pattern of ecological succession. First, the data suggest the wetland was a minerogenic mire in the Iron Age. After that, and since Roman times, it was subjected to dramatic hydrological changes due to the rise of the watertable, fluctuating between the presence of open water and several phases of drawdown. Finally, by ca. 1350 years ago, the wetland experienced a rapid evolution towards ombrotrophy. High grazing pressure was also detected for the last 100 years. The significant change occurred during Early Roman Empire seems to have been the consequence of the direct use of the wetland as a water-reservoir of the canalisation system used for gold-mining. Thus, the current nature of the mire may be the result of an anthropogenic forcing; although multiple anthropogenic and natural causes were potentially linked to the shifts detected, which at least in three phases supposed a threshold response. Our investigation suggests that palaeoecological research is necessary to understand the origin of wetlands ecosystems, their long-term ecology and the role played by human activities. EXPLORING THE CLIMATE RESPONSE TO THE TAMBORA IN 1815 AND THE 1809 TROPICAL ERUPTION Stephan Lorenz. MPI for Meteorology, United Kingdom E-mail address: [email protected]
The largest historic volcanic eruption with known origin was the explosion of Mount Tambora in Indonesia in April 1815. In the aftermath of this devastating eruption, the following year 1816 came to be known as the "year without a summer", in particular in USA, Canada, and Europe, where the worst famine over a century as well as typhus epidemics accompanied by enhanced emigration from Europe were recorded. The stratospheric aerosol mass load was estimated to be about three times that of the Pinatubo eruption in 1991, leading to a strong impact on the Earth's climate system. The additional contribution of the large volcanic eruption with tropical but unknown location occurred in 1809, i.e., six years prior to the Tambora, is not well understood. In a series of ensemble simulations we applied the Earth system model developed at the Max-Planck-Institute for Meteorology, based on the ECHAM5/MPIOM model family, to investigate the combined contribution of the Tambora and 1809 eruptions to the relatively cool climate during the 19th century. However, ensemble simulations of complex circulation models are associated with a large ensemble spread in air temperature on a hemispheric and global as well as on a regional scale, with limited to very strong atmospheric response to volcanic aerosols. The unique path of the climate evolution through the Earth's history yielding the extreme summer in 1816 in North America and Europe is compared with the simulations. A special focus of our analysis is the volcanic impact on climate and its relationship with the status of the climate system, e.g. the ocean circulation, at the time of the eruption. LATE QUATERNARY MEGAFAUNA EXTINCTIONS, AND SURVIVALS
POPULATION
DYNAMICS,
ANTHROPOGENIC FORCING IN WETLANDS: A CASE STUDY IN NW IBERIA
Eline Lorenzen. Centre for GeoGenetics, University of Copenhagen, Denmark
Lourdes Lopez-Merino. Institute for the Environment, Brunel University, United Kingdom
The discussion of the causes underling the Late Quaternary megafauna extinctions has focused primarily on the roles of climate versus humans. Alternative drivers include an extraterrestrial impact, interspecific competition, or hyperdisease. Here we present the first large-scale comparative study addressing the LQ extinctions in the northern hemisphere, using data from several megafauna species.
E-mail address: [email protected]
Wetlands are exceptional ecosystems that contribute to biodiversity and play a key role in the hydrological cycle. Knowledge of their ecology is
E-mail address: [email protected]